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Cozy Mark IV

Cozy Mark IV : Time and Expenses

Chapter 9: Main Landing Gear and Landing Brake

In this chapter you will install the main landing gear and landing brake.


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Chapter 9

# Item Date Cost Time (hrs) Comment
1. Main landing gear strut 2/1/05 $749.00 0 Ordered from Feather Lite.
2 Reinforcing layups 7/3/05 $1,413.07 3 Cut out BID for reinforcing layups over front & middle LG bulkheads.  Laid up the front LG bulkhead reinforcements.  The cost here is the chapter 9 order from Spruce.
3. Reinforcing layups 7/4/05   1 Laid up the middle LG bulkhead reinforcements.
4. Reinforcing layups 7/6/05   2 Cut out BID for layups between aft LG bulkhead and firewall and laid them up.
5. LG strut 7/9/05   8 Measured 95" on the inside of the strut, and cut strut to length, with an 8-degree angle.  Sanded the strut dull with 36-grit.  Put the strut up on the worktable, suspended by nails.  Cut out strips of UNI for the glassing.  Marked 35-degree angles on the strut for reference, painted the strut with epoxy, and laid up 4-lies of UNI.
6. LG strut 7/10/05   3 Trimmed the glass on the strut TE, and sanded it smooth.  Put the strut back on the nails to do the brake line.  I used 3/8" OD vinyl tubing rather than straws, it was pretty easy.  5ME'd the tubing to the strut.  Put micro between the tubing & strut, put aluminum tape on the other side, and laid up a 2-ply BID tape with peel ply.  Left it alone to dry.
7. LG strut 7/12/05   3 Trimmed previous glassing, and reinstalled the strut on the nails, LE up.  Applied micro to the other side of the brake line nylon tubing, painted a coat of epoxy over the strut, and laid up the next 4 plies of the torsional layups, ensuring that each layer was staggered per plans.
8. LG strut 7/13/05   2 Trimmed and sanded yesterday's plies on the strut.  Came out very, very nice!  Cut the 31" plywood board, leveled against the worktable, and leaned the strut against it.  Did all the measurements, leveling, and marking on the floor, plywood & strut, in preparation for building the attach tab box.
9. LG strut 7/14/05   1 Made pieces ABC, made a 30-degree cut on A, traced to match the strut.  Glued B & C to A, left it to dry.
10. Attach tabs 7/16/05   5 Glued C in place, and then bondo'd the jig box to the strut.  Cut pieces D & E and bondo'd / glued them in place.  While that was drying I drew the lines on the work table.  Put the strut up on the table, lined up with the FS lines, and checked the level, which was perfect.  I did have the shim the LE side of the box a bit, to get the LE lined up with FS 108.25 (as revealed by the plum bob).  That done, I bondo'd the jig box to the table, and put down plastic to protect the table from the excess epoxy that would soon be dripping everywhere.  I then cut out all the cloth for the tab layups (25 plies UNI, 20 plies BID).  Mixed up some epoxy, wet the cloth out, and pressed it into place, 5 plies at a time for the UNI, and 4 plies at a time for the BID.  Clamped blocks of wood over the tabs (covered in wax paper), and watched the excess epoxy ooze out of the tabs.  Leaving it there to dry overnight.
11. Attach tabs 7/17/05   8 Took off the clamps & blocks, everything looked very good.  Drilled a hole in a small 2x4 1 13/16" up from the end, which was my reference dimension.  Drilled holes through the tabs using this drill jig.  Then I removed the strut from the jig box and double-checked the holes with the 12" long drill bit, and the fit is good.  I then proceeded to trim the tabs down to the correct size & shape.  I made a 3" round jig out of a small bit of 2x4, drilled a 1/4" hole through it, and fastened it with a bolt to the attach tab.  I then used my jig saw, cutting around this jig to get a nice, round end on the tab.  After I had finished trimming the tabs down I filled the holes with wax and got ready for the next layup.  Cut out the 25 plies of UNI and 20 plies of BID, laid some plastic down on the floor to catch excess epoxy, and leaned the strut against the side of the table.  I decided to take a short break before starting the layup, and in meantime I started to make MG-2 (4).  I don't have the aluminum yet for MG-1, it's on backorder, so I'll have to wait awhile before I can install the strut.  I don't have a #10 drill bit, so I just cut the 1/4" hole in the center of MG-2's.  After dinner I came back and started the attach tab layups.  This went very quickly, since I had done one before.  The only thing I did differently was that I put down strips of packing tape on the strut, along the sides of the tabs, so that when it comes time to trim this layup it'll be easier to remove it from the strut.  Clamped blocks against the inside tabs, and it's now drying.
12. Attach tabs 7/24/05   1 Trimmed the inside portion of the attach tabs, sanded round, double-checked holes.
13. Gear trial fit 7/25/05   2 Trial-fit the gear to the fuselage.  First I raised the fuselage up onto saw horses (with the help of my son), and leveled.  I had a heck of a time getting the 12" long 1/4" bits through.  I'd like to say that all the holes lined up perfectly, but one of them is off by about 1/8", which makes the whole thing difficult to fit.  I widened the hold in the aft bulkhead left side (which is now on the right, since the plane is upside-down), and was finally able to drill the 1/4" bit all the way through on both sides.   Now that that's done, I checked position.  Double-checked level, drew FS 124.25 and FS 108.25 on the floor, and dropped a plumb bob from the strut LE.  The right side (on the left) is forward about 3/4", and the left side is forward about 5/8".  Double-checked that the gear is level by balancing a 2x4 on top with a level on it, and that worked out perfectly.  Regarding the forward LE, I'm going to open up the holes in the bulkheads a bit to allow the strut to tilt back a hair, and incrementally do this until I get proper positioning.
14. Strut & lg cover 7/26/05   2 More trial-fitting with the strut.  I opened up the holes in the aft LG bulkhead a little, to give the strut room to tilt back.  From working with the jig box, I know that small changes at the tabs can cause big changes in the ends, so I'm taking it slow.  My first adjustment didn't result in much change, though, so I am going to put it off until I get the aluminum for MG-1 and do the real install.

In the meantime I started working on the LG cover.  Put duct tape around the flanges, build the ledge with 3/8" PVC, and then built the cover with 3/8" PVC.  Micro'd the joints and left it to dry. 

15. LG cover 7/27/05   1 Glassed outside of LG cover
16. LG cover 7/28/05   1 Glassed inside of LG cover
17. LG cover 7/29/05   1 Drilled & tapped LG cover holes.
18. Landing Brake 7/31/05 $300 4 Cut the LB loose (with difficulty).  Made LB-19 and LB-23 from birch plywood. 5ME'd LB-19 to the 10" hinge.  Cut 3 1" square shims.  Cut 45-deg hole for LB-23 in the fuselage bottom.  And now I've done all I can do for the moment.  I ordered Wayne Lanza's landing brake actuator, so I'm waiting for that.  I'm short on 1/4" aluminum, how did that happen???
19. LB 8/5/05   2 Made 5/8" metal slugs (4), 5ME'd them to LB-23.  Removed foam from fuse bottom to accommodate slugs.  Tacked shims to LB-23.  After reading the FAQ and Rick Maddy's site, I decided to re-make LB-19, and since it was already attached to the hinge, to cut another 10" section of hinge for this purpose.  The reason for this is to better accommodate Wayne Lanza's landing brake actuator.   The FAQ advises that many builders increase LB-19 an inch wider, and Rick reported that this was barely enough.  I made mine 1.5" wider, and centered it where the original one would fit on the hinge.  After doing this, I then tacked the hinge to the shims (LB-19 to LB-23).
20. LB / LG 8/6/06   6 Today was an exercise in frustration.  The 1" shims are really too big, and interfere with the hinge (not to mention making it easy to get 5ME into the hinge, which I've decided is A Bad Thing).  So I cut new shims at 3/4" x 1", and re-attached LB-19 to LB-23.  After this was done I realized that I had mis-positioned the 5/8" metal slugs, they were too high (so in order to drill into them, I'd be drilling through the hinge part of the hinge, which was Another Bad Thing).  The problem was that I had measured .75" to the bottom of the slug, not to the middle of the slug.  What was that someone once said about measuring twice?  Anyway, removed the slugs, re-positioned (CORRECTLY), and then attached the whole hinge assembly to the LB with flox.  While this business was drying, I returned to the landing gear.  Re-confirmed that the fuselage is level, re-drew reference FS lines on the floor (with Alec's help!), and re-installed the gear.  I had made small adjustments to the holes through the LG bulkheads, and it paid off.  The right LE was .2" forward, and the left LE was about .15" forward, which is within the tolerance specified in the plans (.25").  So rather than continue to elongate the bulkhead holes, I'll make up for it when I install the wheels.
21. LG 8/7/05   7 Re-checked the LG position (one last time!).  Bondo'd MG-1s in place, removed the strut.  Bolted MG-2s in place.  Drilled #10 holes through pilot holes in MG-2s, through bulkheads, and through MG-1s.  This was hard!  My poor, cordless drill couldn't keep up, so I finally invested in a corded drill, which made quick work of this.  I then removed the MG-2s and countersunk the holes, and expanded the 1/4" holes to 5/16".  Removed MG-1s, sanded off the bondo, prepared the mating surfaces, and floxed the MG-1s and MG-2s in position.  This turned out to be one of the hardest things I've done so far on this whole job.  I drilled the holes and verified alignment, but when I put the MG-1/2s back in position, the holes no longer lined up.  Doesn't seem possible.  I didn't mix up the plates, they were all carefully marked.  Well crap.  So I had to re-drill some of the holes (just expanding them a bit), to allow the bolts to go through (this, while the flox is drying).  Not fun.  And now I've realized that I also don't have the 2 MK100 steel studs, so I'm at a dead end for now with the gear.  I am also waiting for the LB actuator, so I may have to proceed to chapter 10, cutting the foam for the canard, while I'm waiting for these things to arrive.
22. Brock parts 7/29/05 283.65   Various parts from Brock (MK100s, MKMG4s, MKMGAs, ...).
23. LG tabs 8/9/05 41.45 .5 Opened up the holes in the tabs in the LG strut to 3/4", using the spot-facing tool.  Ordered the MK100 steel studs from Wicks.
24. LB 8/13/05   1 Bondo'd 2 boards to the LB, micro'd LB-23 to the fuselage bottom.
25.   8/14/05   2 Popped the LB and hinge loose from LB-23, removed shims.  Sanded the depression 1/8".  To do this I put a depth gauge on my dremel to 1/8", and created a series of 1/8" deep lines all over the depression.  I then sanded with a sanding block until the depressions were smoothed out.  Sanded the 1" wide glassed area around the depression.  Radiused the edges.
26. LG 8/24/05   2 Finished LG bulkhead drilling.
27. LG 8/26/05   3 Adjusted holes in LG attach tabs.  Floxed bushings to LG bulkheads.
28. LG 8/27/05   2 Floxed MKMGA's in place.  Aligned LG position to FS lines on the ground.  1/8th off on the left, 0.0 off on the right.  Then checked the fit of the LG cover, and it does NOT fit.  What?!  After some study and review it looks like I positioned the holes in the LG attach tabs too high, and so the gear does not sit deep enough in the fuselage.  I then removed the MKMGA's before the flox set, because it's clear that I'll need to fix this before I go on.
29. LG 8/28/05   2 Drilled new holes in tabs, after figuring out the problem.  The plans state that the attach points should be .75" higher than the highest point on the strut.  But that's not correct; it's not the highest point on the strut, but the highest point at 13" from the center of the strut.  Maybe I'm too literal-minded.  Anyway, not too difficult to fix, just severely annoyed.  Positioned the LG strut with the NEW 1/4" holes to the fuse bottom with the 12" long 1/4" drill bits.
30. LB 9/4/05   2 Made 2 LB-18 brackets.  Cut the hole in the fuse bottom for the actuator.  For this I followed the dimensions described by Rick Maddy, and then trial fit everything in place.
31. LB 9/7/05   3 Sanded glass inside LB cutout.  Cut glass cloth.  Micro'd all the little dents and divots, wet out the glass and applied the layup over the LB cutout.  After about 2 hours came back and knife-trimmed.
32. LB 9/11/05   2 Trial-fit LB to fuselage.  I fixed a hole that was left over from when I removed the LB (up there in entry #18) by cutting it out and replacing it with new foam cut-to-fit, radius'd all the corners, filled some small holes with dry micro, sanded the bare glass, and then applied 3-plies BID overall.  While it was drying I covered the LB hole with plastic, and a few hours later knife-trimmed the LB cover, and placed it in the fuselage LB hole, weighted down. 
33. LB 9/12/05   .5 Well, when I checked on the LB tonight, apparently the hinge had not remained in contact with LB-23.  As I was removing the plastic that protected the fuse from the drying LB, it popped loose.  So I sanded off the dried flox, (took advantage of the opportunity to sand the edges of the LB smooth), and re-floxed the LB hinge to LB-23.  So we'll check back tomorrow.  It appears to have good contact, but I thought it was secure yesterday, too.
34. LB 9/13/05   1 Drilled and tapped holes through hinge for bolts.
35. LB 9/18/05   .5 Bolted LB-18 brackets to LB.  Trial-fitting the Lanza actuator.
36. LB 4/24/06   .5 Bolted the actuator in place.  The AN4-26A bolts that came with it were not quite long enough after I added a 2-ply BID reinforcement on each side of the center keel.  Used 2 AN4-30A bolts instead.
37. Strut 5/15/07   2 Test fit axle and caliper, marked area to trim from strut for caliper.  Used dremel to create quite an impressive S-glass dust storm!
38. Strut 5/16/07   2 Finished cutting strut to fit calipers.  Put on 3 plies of BID over strut ends, let it get tacky.  Floxed axles in place, held with clamps.  Used laser level to ensure proper alignment to the 1/4-deg marks on the wall.
39. Strut 5/17/07   1 Trimmed the glass and aluminum backing around the strut, and did a little more sanding to allow the calipers to fit.  Attached wheels, calipers.  Amy helped me turn the plane over.  Cut out gear box foam.  Ran brake lines, cut holes in forward LG bulkhead.
40. LG box 5/18/07   2 Layup BID on LG bulkhead cover, let cure.  Installed with flox, let cure.  After almost 2 years, this chapter is DONE!

Chapter total: Time 92, Cost $2,787.17

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Last modified: Saturday, May 19, 2007